disable jit on some modules on android

to make koreader on Android  more stable

and with these opt params:
```
require("jit.opt").start("sizemcode=64","maxmcode=64", "hotloop=10000")
```

The strategy here is that we only use precious mcode memory (jitting)
on deep loops like the several blitting methods in blitbuffer.lua and
the pixel-copying methods in mupdf.lua. So that a small amount of mcode
memory (64KB) allocated when koreader is launched in the android.lua
is enough for the program and it won't need to jit other parts of lua
code and thus won't allocate mcode memory any more which by our
observation will be harder and harder as we run koreader.

frontend/cache.lua

@@ -6,6 +6,10 @@ local lfs = require("libs/libkoreader-lfs")
 local DataStorage = require("datastorage")
 local DEBUG = require("dbg")
 
+if require("device"):isAndroid() then
+    require("jit").off(true, true)
+end
+
 local function calcFreeMem()
     local meminfo = io.open("/proc/meminfo", "r")
     local freemem = 0

frontend/ui/rendertext.lua

@@ -8,6 +8,10 @@ local CacheItem = require("cacheitem")
 local BlitBuffer = require("ffi/blitbuffer")
 local DEBUG = require("dbg")
 
+if require("device"):isAndroid() then
+    require("jit").off(true, true)
+end
+
 --[[
 @TODO: all these functions should probably be methods on Face objects
 ]]--

frontend/ui/widget/container/inputcontainer.lua

@@ -5,6 +5,10 @@ local Geom = require("ui/geometry")
 local Event = require("ui/event")
 local _ = require("gettext")
 
+if require("device"):isAndroid() then
+    require("jit").off(true, true)
+end
+
 --[[
 an InputContainer is an WidgetContainer that handles input events
 

frontend/ui/widget/container/widgetcontainer.lua

@@ -1,6 +1,10 @@
 local Geom = require("ui/geometry")
 local Widget = require("ui/widget/widget")
 
+if require("device"):isAndroid() then
+    require("jit").off(true, true)
+end
+
 --[[
 WidgetContainer is a container for another Widget
 --]]

platform/android/luajit-launcher

@@ -1 +1 @@
-Subproject commit caca2fd844d90a4828f60c7bb1003702d4936472
+Subproject commit e3560e777558efbb1dc913250024afa7ecb40868